A Limpopo high school is under investigation after 18 pupils were allegedly forced to strip half naked because they forgot their calculators at home.

Police spokesperson Colonel Moatshe Ngoepe said no arrests were made in connection with the allegations, which include that the 18 Ntwampe High School pupils were ordered to remove their shirts and "sit in the sun at the assembly" last Thursday.

Provincial education department spokesperson Sam Makondo said the incident was reported on Monday and added that the matter would be investigated.

"We have to wait for him to return to school so that we can process what needs to be processed," he told News24.

Makondo said it was alleged that the pupils – all in Grade 10 - were told to remove their shirts.

He said parents had met at the school on Monday to "discuss the matter" and "expressed concern over what happened".